Kinds Of Fibula Fractures

The fibula bone is the outer bone of the ankle and is the most common bone broken with an ankle fracture. Most fibula fractures are the result of rotational forces that cause the bone to snap. Depending on the type of rotational injury the fibula bone can break at several locations on the bone, which partly determine the severity of the ankle fracture as well as the need for ankle fracture surgery.

Important ​Ankle Anatomy

A brief lesson in leg anatomy is important to understand how fibular fractures impact ankle fractures. The fibula bone, together with the tibia bone, make up the lower leg bone. The fibula starts just below the knee and extends to the outer part of the ankle. A strong thick ligamentous membrane keeps the two leg bones bound together. An important strong ligamentous connection is present at the ankle level that securely holds the fibular bone to the tibia bone, and is called the ankle syndesmosis. The foot is interlocked into the leg bones and supported with a strong ligamentous network. The overall human design of the ankle creates a situation where the outer aspect of the ankle, where the fibula is located, more susceptible to injury.

The 5 Kinds of Fibular Fractures

There are 5 kinds of fibular fractures as it relates to ankle fractures. They are classified based on the anatomic location where the fibula fracture occurs in relation to the ankle joint.

  1. Fibular Fracture At The Knee Joint
  2. Fibula Fracture Above The Ankle Joint
  3. Fibula Fracture At The Ankle Joint
  4. Fibula Fracture Below The Ankle Joint
  5. Fibula Avulsion (or Chip) Fractures

Fibula Fracture At The Knee

A fibula fracture by the knee joint is often part of ankle fracture. Dr. Neal Blitz /

Fibular fractures that occur in close proximity to the knee joint (called Maisonneuve Fracture) are generally classified as a special type of ankle fracture. Specific rotational forces can transmit the force all the way up the leg and rupture the strong membrane between the leg bones in addition to the fibula fracture. These fractures are typically unstable and surgery is often recommended.

Fibula Fracture Above The Ankle Joint

Fibular fractures that occur higher than the ankle joint level are usually unstable and require surgery. Dr. Neal Blitz /

Fibular fractures that occur above the joint line of the ankle joint (also called high ankle fractures) are also mostly considered surgical fractures because their presence indicates instability of the ankle joint. With these fractures, the strong ligamentous interconnection between the tibia and fibula (the syndesmosis) is generally disrupted as well. The injury forces that cause this injury also injure the tibia bone and/or its ligaments on the inside of the ankle.

Fibula Fracture At The Ankle Joint

Fibula fractures at the ankle joint line are the most common ankle fracture that undergoes surgery. Dr. Neal Blitz /

Fibular fractures that occur at the ankle joint line are the most common type of operative ankle fracture. They are usually diagonally oriented starting at the joint line and extend upwards. These fractures are often rotational injuries to the ankle and depending on the force of the initial injury may require surgery.

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Fibula Fracture Below The Ankle Joint

Fibular fractures that occur below the ankle joint line tend to be horizontally oriented fractures. They occur when a force pushes the foot inward causing the fibula to snap.

Fibula Avulsion (or Chip) Fractures

These small chip fractures are generally a sign of ligament rupture of the outer ankle. Instead of the force causing a broken bone, rather the ligaments snap where they attach to the bone. A small piece or fleck of bone is pulled off (avulsed) with the ligament rupture. The presence of an avulsion fracture may be a sign of a more complex ankle fracture. Without a co-existing fracture of the tibia bone, some surgeons don’t necessarily consider the small fleck avulsion fracture a true fracture but rather a just an advanced ankle sprain or ligament rupture.

When To Have Fibula Fracture Surgery

The fibula fracture needs to be evaluated in the context of the complete ankle injury when considering surgery. Ankle fractures generally occur as rotational injuries and the fibula fracture is one component of the ankle fracture. In general, fibular fractures that are gapped open, displaced and/or angulated generally call for a surgical correction. Any instability is also an indicator for surgery. In some cases, surgeons may tell directly from the fracture and its mechanism whether or not the fracture is unstable and requires surgery. The surgical repair of the fibular fracture depends on fracture pattern. The broken bones may be repaired with wires, screws and/or screws with a plate. Most commonly fibular fractures tend to be fixated with a single screw that hold the broken bones together, and a supporting plate with screws that span the broken bone. It's important to recognize that not all fibular fractures require surgery. With or without ankle fracture surgery, it takes the bones 6-8 weeks to heal after broken. The purpose of any surgery does not speed up the time it takes to heal the bone but rather the purpose of the surgery is generally to stabilize the bone segments to heal in the proper position.

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